I have an unfired brown box tempest that I paid £275 for from a dealer and an as new older black boxed tempest with a paperwork and accesories that I paid £250 for as a private sale
They seem to be going up I price lately so expect to pay £200-250 for a nice boxed example
£140-170 for a tidy unboxed example and £100-£120 for a used working condition example